The present invention encompasses articles and methods for providing softening and antistatic benefits to fabrics in an automatic laundry dryer. More specifically, damp fabrics are commingled with a formic acid salt of a long chain primary amine in an automatic clothes dryer and are provided with a soft, antistatic finish concurrently with the drying operation. The softening and antistatic formic acid salt of a long chain primary amine is preferably employed in combination with a dispensing means adapted for use in an automatic dryer.
Treatment in an automatic clothes dryer has been shown to be an effective means for imparting desirable tactile properties to fabrics. For example, it is becoming common to soften fabrics in an automatic clothes dryer rather than during the rinse cycle of a laundering operation. (See Gaiser, U.S. Pat. No. 3,442,692, issued May 6, 1969.)
Fabric "softness" is an expression well-defined in the art and is usually understood to be that quality of the treated fabric whereby its handle or texture is smooth, pliable and fluffy to the touch. Various chemical compounds have long been known to possess the ability to soften fabrics when applied to them during a laundering operation.
Fabric softness also connotes the absence of static "cling" in the fabrics, and the commonly used cationic fabric softeners provide both softening and antistatic benefits when applied to fabrics. Indeed, with fabrics such as nylon and polyester, the user is more able to perceive and appreciate an antistatic benefit than a true softening benefit.
Fatty alkyl cationic antistatic softening compounds and compositions designed for application to fabrics in an automatic dryer have been the subject of recent innovations. (See, for example, Furgal, U.S. Pat. No. 3,634,947, issued Jan. 18, 1972, and Morton, U.S. Pat. No. 3,686,025, issued Aug. 22, 1972.) Other fatty materials have been suggested for use as dryer-added fabric softeners. (See, for example, Hewitt et al., U.S. Pat. No. 3,676,199, issued July 11, 1972.) Included among these prior softening compositions are various glycerides in combination with oil-soluble, lower-ethoxylated surfactants. Triglyceride fabric treating agents are disclosed in Bernholz et al., U.S. Pat. No. 3,785,973, issued Jan. 15, 1974.
The use of primary amines and the salts of such amines as fabric conditioning agents for use in the washing and rinsing cycles of an automatic washer, as well as the drying cycle of an automatic dryer has been disclosed. (See for example, Blomfield, U.S. Pat. No. 3,095,373, issued June 25, 1963; Gaiser, U.S. Pat. No. 3,442,692, issued May 6, 1969; and South African Pat. No. 69/3923.) The use of primary amines in a dryer context, however, causes odor problems and paint softening. These problems are overcome with some salts, but not predictably so.
Formic acid salts of primary amines have also been used to treat fibers. (See for example Japanese Pat. No. 69-23,891 issued Oct. 9, 1969, and British Pat. No. 1,101,877, issued Jan. 31, 1968.) These references do not, however, disclose the advantages of using the formic acid salt in the dryer context over other acid salts and the straight amines or the superior fabric performance the formic acid salt gives as compared with quaternary ammonium salts in the dryer.
It is, therefore, an object of this invention to provide a superior article of manufacture adapted for imparting softness and antistatic benefits to fabrics in a clothes dryer, alternatively in a clothes washer, particularly in the rinse cycle of the washer, while not softening paint or having bad amine odors.
It is another object of this invention to provide a superior method for conditioning fabrics in a clothes dryer or a clothes washer.
These and other objects are obtained herein, as will be seen from the following disclosure.